JP6436906B2 - Sodium-halogen secondary battery - Google Patents

Description

  This application enjoys priority from US Provisional Patent Application No. 61 / 697,608, filed Sep. 6, 2012 (Title of Invention: Sodium-Halogen Battery). This application further enjoys the priority of US Provisional Patent Application No. 61 / 777,967 (Title of Invention: Sodium-Halogen Secondary Battery) filed March 12, 2013. This application further enjoys the priority of US Provisional Patent Application No. 61 / 781,530 (Title of Invention: Sodium-Halogen Secondary Flow Battery) filed March 14, 2013. This application further enjoys the priority of US Provisional Patent Application No. 61 / 736,444 filed Dec. 12, 2012 (Invention: Battery having bromine or bromide electrode and sodium selective membrane). All of these prior applications are incorporated herein by reference.

  Federal Government Statement: This invention was made with federal government support under contract number 1189875 awarded by Sandia National Laboratory. The government has certain rights in the invention.

  The present invention relates to a battery. Specifically, the present invention provides a sodium-based secondary battery (or rechargeable battery) having a liquid cathode solution comprising a sodium ion conductive electrolyte membrane and a halogen and / or a compound.

  Batteries are used to store and release electrical energy for various applications as is well known. In order to produce electrical energy, batteries typically convert chemical energy directly into electrical energy. A cell typically includes one or more galvanic cells consisting of two half-cells that are electrically isolated except in communication with an external circuit. During discharge, electrochemical reduction occurs at the positive electrode, while electrochemical oxidation occurs at the negative electrode of the battery. Although the positive and negative electrodes in a battery are not in physical contact with each other, they are usually at least one (or more) ionic conductive and electrically insulating, in a solid state, a liquid state, or a combination thereof It is chemically connected by an electrolyte. When an external electrode or external load is connected to a terminal connected to the negative electrode and a terminal connected to the positive electrode, the battery conducts electrons through the external circuit and the ions move through the electrolyte.

  Batteries are classified into various methods. For example, a battery that is completely discharged only once is called a primary battery or a primary cell. On the other hand, a battery that can be repeatedly discharged and charged once or more is called a secondary battery or a secondary cell. The performance of a cell or battery that can be charged and discharged multiple times depends on the Faraday efficiency of each charge and discharge cycle.

  Sodium-based rechargeable batteries are composed of a variety of materials and configurations, but many, if not all, sodium batteries that require high Faraday efficiency include solid primary electrolyte separators such as solid ceramic primary electrolyte membranes. use. The main advantage of using a solid ceramic primary electrolyte membrane is that the Faraday effect of the battery reaches 100%. Indeed, the battery configuration and electrode solution of most other batteries can be internally mixed over time, thereby reducing Faraday efficiency and losing battery capacity.

  Primary electrolyte separators used in sodium batteries that require high Faraday efficiency often consist of a porous material containing an ion conducting polymer, an ion conducting liquid or gel, or a dense ceramic. In this regard, many commercially available rechargeable sodium batteries consist of a molten sodium metal anode, a sodium β ″ -alumina ceramic electrolyte separator, and a molten cathode containing molten sulfur and a carbon composite (sodium / Called sulfur battery). Although these conventional high temperature sodium-based rechargeable batteries have a relatively high specific energy density, the power density is not so high, such rechargeable batteries are generally required to have a high specific energy, but high It is used for certain special applications that normally do not require power, such as stationary power supplies and uninterruptible power supplies.

  Despite the advantages associated with conventional sodium-based rechargeable batteries, such batteries also have significant drawbacks. In certain instances, sodium β ″ -alumina ceramic electrolyte separators are generally more conductive at temperatures above about 270 ° C., and better wettability with molten sodium, and / or molten cathodes. Many conventional sodium-based rechargeable batteries are at temperatures above about 270 ° C. because they typically require relatively high temperatures (eg, temperatures of about 170 ° C. or 180 ° C.) in order to maintain a molten state. Operates and is exposed to serious thermal management and heat sealing problems. For example, some sodium-based rechargeable batteries are difficult to dissipate heat from the battery or maintain the negative and positive electrodes at relatively high operating temperatures. In other examples, the relatively high operating temperature of certain sodium-based batteries creates significant safety issues. In yet another example, the relatively high operating temperature of certain sodium-based batteries requires components that can withstand and operate at such high temperatures. Accordingly, such members are relatively expensive. In yet another example, such a battery is costly to operate and energetically inefficient because it requires a relatively large amount of energy to heat a conventional sodium-based battery to a relatively high temperature. .

  Although sodium-based rechargeable batteries can be used, there are also challenges associated with batteries including the aforementioned problems. Therefore, there is an increasing demand for improvement of conventional sodium-based rechargeable batteries in this field and substitution for other sodium-based rechargeable batteries.

  The present invention provides a sodium-halogen secondary battery. While the sodium-halogen secondary battery described may include any suitable component, in certain embodiments, the battery includes a negative electrode chamber that houses a negative sodium-based electrode. In such embodiments, the battery also includes a positive electrode chamber that houses a current collector disposed in a liquid positive electrode solution containing halogen and / or a halogen compound. The battery further includes a sodium ion conductive electrolyte membrane that separates the negative electrode from the liquid positive electrode solution.

The negative electrode may comprise any suitable sodium-based anode, and in certain embodiments, the negative electrode comprises sodium metal that is in a molten state during battery operation. In other embodiments, however, the negative electrode may consist of a sodium anode or sodium intercalated carbon (sodium intercalated carbon) that remains as a solid upon battery operation. In such embodiments where the negative electrode remains as a solid upon battery operation, the battery includes a non-aqueous anolyte solution (non- aqueous negative electrode solution ) disposed between the negative electrode and the electrolyte membrane.

  A sodium ion conducting electrolyte membrane selectively transports sodium ions (referred to herein as a suitable separator), is stable at the operating temperature of the battery, and contains a positive electrode solution and a negative electrode (or non-aqueous anolyte). Any film may be used as long as it is stable even when contacted and can achieve a desired battery function. Indeed, in certain embodiments, but not limited to, the electrolyte membrane is a NaSICON-type membrane that is substantially impermeable to water (eg, NaSELECT® membrane, manufactured by Ceratech, Salt Lake City, Utah). Consists of. Therefore, in such an embodiment, since the water non-permeable electrolyte membrane is used, the positive electrode solution may be composed of an aqueous solution that reacts violently when in contact with the sodium negative electrode.

The current collector in the positive electrode chamber may be made of any suitable material as long as the battery functions as desired. In practice, but not limited to this, the current collector comprises a wire, felt, mesh, plate, tube, sponge (foam) or other suitable current collector structure. Further, the current collector may be composed of any suitable material, but in certain embodiments, carbon, platinum, copper, nickel, zinc, sodium intercalation cathode materials (eg, Na _x MnO ₂ ). And / or other suitable current collector materials.

  The liquid cathode solution in the cathode chamber may be made of any suitable material as long as it can conduct sodium ions to and from the electrolyte membrane and the battery functions as desired. Examples of suitable cathode solution materials include, but are not limited to, aqueous solvents that can easily conduct sodium ions and are chemically compatible with the electrolyte membrane (eg, dimethyl sulfoxide, NMF (N-methylformamide), etc. ) And non-aqueous solvents (eg, glycerol, ionic liquids, organic electrolytes, etc.). Further, in some embodiments, the positive electrode solution comprises molten fluorosulfonylamide (eg, 1-ethyl-3-methylimidazolium- (bis (fluorosulfonyl) amide) ([EMIM] [FSA])).

  The positive electrode solution is composed of halogen and / or a halogen compound. Examples of suitable halogens include bromine, iodine and chlorine. Similarly, examples of suitable halogen compounds include bromide ions, polybromide ions, iodide ions, polyiodide ions, chloride ions and polychloride ions. The halogen / halogen compound is introduced into the cathode solution by a suitable method. In certain embodiments, they are added as NaBr, NaI or NaCl.

In certain embodiments, the described battery is modified to limit the amount of freely floatable halogen present in the cathode solution and / or in the cathode chamber. The amount of halogen in the battery can be reduced and / or controlled by any suitable method, and in certain embodiments, the method comprises (1) a sufficient amount of sodium halogen compound (eg, NaBr, NaI, etc.) and / or halogen. A method comprising forming a polyhalogen compound (eg, Br ₃ ⁻ , I ₃ ^—, etc.) from free halogen in the positive electrode solution containing a molecule (eg, bromine, iodine, etc.), (2) a halogen compound in the positive electrode solution Complexing agents such as tetramethylammonium bromide, tetramethylammonium iodide, N-methyl-N-methylmorpholine bromide, which form adducts (adducts or other complexes) with halogens and / or polyhalogen compounds , N-methyl-N-methylmorpholine iodide), (3) oxidation to halo in solution A current collector made of a metal (eg, copper, nickel, zinc, etc.) that forms a metal ion that can react with a metal compound ion before the halogen compound ion in solution is oxidized to form the corresponding halogen. By using a current collector capable of forming a halogen compound (for example, CuBr, CuI, NiBr ₂ , NiI ₂ , ZnBr ₂ , ZnI _2, etc.), the method according to (4) or a preferred combination thereof can be mentioned.

In certain embodiments, when the battery is operating at an elevated temperature, an excess of the sodium halide compound will form a complex with the formed halogen so that this component remains in solution (so as not to be converted to a gas). It is preferred to include (eg, excess I ₂ , Br ₂ ) or complexing agents. In fact, in some embodiments, NaI (sodium halide or complexing agent) may be added up to 1/3 or more. Furthermore, in certain embodiments employing I _2, the outer frame of the battery, the inner portion Teflon made best stainless steel having (registered trademark), other parts, such as less expensive other types of stainless steel Materials may be used. In another embodiment, the cathode chamber is formed from polyetheretherketone (PEEK) with a Teflon backing. Teflon (registered trademark) is a registered trademark of DuPont.

  In certain embodiments, the battery has a first reservoir in fluid communication with the positive electrode chamber. In such an embodiment, the first reservoir is connected to a first pump mechanism configured to flow the liquid cathode solution from the first reservoir to the cathode chamber and through the current collector. In some embodiments, the battery further includes a second fluid flow reservoir in fluid communication with the negative electrode chamber. In such an embodiment, the second reservoir is connected to a second pump mechanism configured to flow a molten negative electrode (or non-aqueous anolyte) from the second reservoir to the negative electrode chamber.

  The described secondary battery may be operated at any suitable operating temperature. Certainly, in embodiments where the negative electrode is in a molten state when the battery is operating, the battery functions between about 100 ° C. to about 150 ° C. (eg, about 120 ° C. ± about 10 ° C.) (eg, Discharge or charge). Further, in embodiments where the negative electrode remains in a solid state upon battery operation, the temperature of the negative electrode can be kept below about 60 ° C. (eg, about 20 ° C. ± about 10 ° C.). In further embodiments, the battery may be designed to operate below 250 ° C, or below 200 ° C, or below 180 ° C, or below 150 ° C.

  These aspects and advantages of embodiments of the present invention will become more fully apparent from the following description and appended claims.

  The present invention can provide a sodium-based secondary battery (or rechargeable battery) having a liquid cathode solution composed of a sodium ion conductive electrolyte membrane and a halogen and / or a compound.

FIG. 1 is a schematic diagram of a representative embodiment of a sodium-halogen secondary battery comprising a molten sodium negative electrode when the battery is in a discharged state. FIG. 1A is a schematic diagram of an exemplary embodiment of a sodium-halogen secondary battery comprising a molten sodium negative electrode and a pump mechanism when the battery is in a discharged state. FIG. 2 is a schematic diagram of an exemplary embodiment of a sodium-halogen secondary battery comprising a molten sodium negative electrode when the battery is in a recharged state. FIG. 2A is a schematic diagram of an exemplary embodiment of a sodium-halogen secondary battery comprising a molten sodium negative electrode and a pump mechanism when the battery is in a recharged state. FIG. 3 is a cross-sectional perspective view of a representative embodiment of a sodium-halogen secondary battery having a tubular design in which at least a portion of the negative electrode chamber is disposed within the positive electrode chamber of the battery. FIG. 3A is a cross-sectional perspective view of another exemplary embodiment of a sodium-halogen secondary battery having a tubular design in which at least a portion of the negative electrode chamber is disposed within the positive electrode chamber of the battery. FIG. 4 is a schematic view of a representative embodiment of a sodium-halogen secondary battery comprising a solid negative electrode and a non-aqueous anolyte disposed between the negative electrode and a sodium conductive solid electrolyte membrane. FIG. 4A is a schematic diagram of an exemplary embodiment of a sodium-halogen secondary battery consisting of a solid negative electrode, a pump mechanism and a non-aqueous anolyte disposed between the negative electrode and a sodium conductive solid electrolyte membrane. FIG. 5A is a cross-sectional photomicrograph of a representative embodiment of a suitable NaSICON type material for use with embodiments of the present invention. FIG. 5B is a cross-sectional photomicrograph of a representative embodiment of a suitable NaSICON type material for use in embodiments of the present invention. FIG. 6 is a schematic diagram of an exemplary embodiment of a sodium-halogen secondary battery in which the positive electrode solution in the battery is composed of a molten sodium halogen compound and molten sodium fluorosulfonylamide. FIG. 6A is a schematic diagram of an exemplary embodiment of a sodium-halogen secondary battery in which the positive electrode solution in the battery is composed of a molten sodium halogen compound and a molten sodium fluorosulfonylamide and has a pump mechanism. FIG. 7A is a schematic diagram of a representative embodiment of a sodium-halogen secondary battery having a pump mechanism configured to flow a positive electrode solution through the positive electrode chamber of the battery and a negative electrode through the negative electrode chamber of the battery. It is. FIG. 8 is a graph showing experimental results obtained from an operational test of a representative embodiment of a test battery. FIG. 9 is a graph showing experimental results obtained from an operational test of a representative embodiment of a test battery. FIG. 10 is a graph showing experimental results obtained from an operational test of a representative embodiment of a test battery. FIG. 11 is a graph showing experimental results obtained from an operational test of a representative embodiment of a test battery. FIG. 12 is a graph showing experimental results obtained from an operational test of a representative embodiment of a test battery. FIG. 13 is a graph showing experimental results obtained from an operational test of a representative embodiment of a test battery. FIG. 14 is a schematic diagram of another battery according to the present invention. FIG. 15 is a schematic diagram of another battery according to the present invention. FIG. 16 is a schematic diagram of another battery according to the present invention. FIG. 17 is a schematic diagram of another battery according to the present invention.

  Throughout this specification "an embodiment," "one embodiment," or similar terms refers to a specific gist, structure, and performance that is described in connection with the embodiments in at least one implementation of the invention. It is meant to be included in the embodiment. Thus, throughout this specification "in one embodiment", "in one embodiment", "in another embodiment" and similar terms may all refer to the same embodiment, and are not necessarily so. It does not have to be. Furthermore, the following description refers to several embodiments and examples of the various components and gist described in the present invention, but all of the described embodiments and examples are merely illustrative in all respects. It should be understood that the present invention is not limited to these methods in any way.

  Furthermore, the described subject matter, structures, and characteristics of the invention may be combined in any suitable manner in one or more embodiments. For a thorough understanding of embodiments of the present invention, the following are given as a number of specific description examples such as sodium-based anodes, liquid cathode solutions, current collectors, sodium ion conducting electrolyte membranes, and the like. One skilled in the art will appreciate that the present invention can be practiced without one or more specific descriptions or with other specific descriptions, other methods, components, materials, and the like. In other embodiments, well-known structures, materials, and operations have not been described or described in detail so as not to obscure the subject matter of the present invention.

  Since the secondary battery can be discharged and charged as described above, the configuration and method of both states of the battery are described herein. The term “recharge” has various types and has the meaning of a second charge, but one skilled in the art understands that the recharge discussion is valid for the first or initial charge and vice versa. It will be possible. Therefore, for purposes of this specification, the terms “recharge”, “recharged” and “rechargeable” can be replaced with the terms “charge”, “charged” and “chargeable”, respectively. is there.

  An embodiment of the present invention provides a sodium-halogen secondary battery having a negative electrode composed of sodium and a liquid positive electrode solution composed of at least one of halogen and a halogen compound. Although the battery described herein can be composed of any suitable component, FIG. 1 shows a positive electrode comprising a negative electrode chamber 15 containing a sodium-based negative electrode 20 and a current collector 30 disposed in a liquid positive electrode solution 35. A representative embodiment of the sodium-halogen secondary battery 10 comprising the chamber 25, a sodium ion conductive electrolyte membrane 40 for separating the negative electrode from the positive electrode solution, a first terminal 45, and a second terminal 50 is shown. . In order to better understand the battery 10 described, what the battery functions are briefly described below. In the following description, each component of the battery shown in FIG. 1 will be described in more detail.

Describing how the sodium-halogen secondary battery 10 functions, the battery will function almost in any suitable manner. One example is shown in FIG. In FIG. 1, the battery 10 is in a discharged state, electrons (e ⁻ ) flow from the negative electrode 20 (for example, via the first terminal 45), and sodium oxidizes from the negative electrode 20 to form sodium ions (Na ⁺ ). To do. FIG. 1 shows that these sodium ions are transferred from the sodium-based negative electrode 20 to the positive electrode solution 35 through the sodium ion conductive electrolyte membrane 40, respectively.

A contrasting example is shown in FIG. In FIG. 2, the secondary battery 10 is in a recharged state, and electrons (e ⁻ ) flow from an external power source (not shown) such as a charger to the sodium-based negative electrode 20 and the battery 10 is discharged (shown in FIG. 1). The opposite chemical reaction occurs. Specifically, as shown in FIG. 2, when the battery 10 is in a recharged state, sodium ions (Na ⁺ ) are respectively transferred from the positive electrode solution 35 to the negative electrode 20 via the electrolyte membrane 40, and sodium ions Is reduced to form sodium metal (Na).

  The various components of the battery 10 will be described. The battery 10 (as described above) includes a negative electrode chamber 15 and a positive electrode chamber 25. In this regard, these two chambers may be of any suitable shape or size and may have other suitable characteristics provided that the battery 10 performs the desired function. For example, the negative electrode chamber and the positive electrode chamber may be tubular, rectangular, or other suitable shape. Further, these two chambers may have any suitable spatial relationship with each other. For example, FIG. 2 shows an embodiment in which the negative electrode chamber 15 and the positive electrode chamber 25 are close to each other, and FIG. 3 shows that at least a part of one chamber (eg, the negative electrode chamber 15) is another chamber (eg, the positive electrode chamber). One embodiment is shown in which the contents of the two chambers are separated by the electrolyte membrane 40 and other partitions, which are arranged in the chamber 25).

  Regarding the negative electrode 20, the battery 10 may be composed of any suitable sodium-based negative electrode 20 as long as the battery 10 performs a desired function (for example, discharging and charging). Suitable examples of sodium-based negative electrode materials include, but are not limited to, sodium alloy and sodium intercalation materials consisting of substantially pure sodium, other suitable sodium-containing negative electrode materials. Indeed, in certain embodiments, the negative electrode comprises or consists solely of a predetermined amount of substantially pure sodium. In other embodiments, the negative electrode comprises or consists solely of a sodium intercalation material.

In the case where the negative electrode 20 is made of a sodium intercalation material, the intercalation material is formed by the sodium metal in the negative electrode being oxidized during the discharge of the battery 10 to form sodium ions (Na ⁺ ), and the sodium is being recharged while the battery is being recharged. It may be made of any suitable material that has the function of allowing ions to be reduced and inserted into the intercalation material. In some embodiments, the intercalation material is also composed of a material that does not substantially increase the resistance of the electrolyte membrane 40 (described below). In other words, in some embodiments, the intercalation material can easily penetrate sodium ions and does not adversely affect the rate at which sodium ions permeate from the negative electrode chamber 15 to the positive electrode chamber 25 (and vice versa).

  In some embodiments, the intercalation material in the anode 20 is sodium metal (and, for example, graphite, mesoporous carbon, boron doped diamond, carbon and / or graphene) (and (Or sodium metal alloy). Thus, in some embodiments, the negative electrode comprises a sodium-inserted carbon material.

  When the battery 10 is operated (for example, discharging and / or charging), the temperature of the sodium-based negative electrode 20 may be any suitable temperature as long as the battery functions as desired. Indeed, in certain embodiments (eg, embodiments in which the negative electrode is sodium metal), the battery may function at any operating temperature provided that the negative electrode is molten during operation of the battery. Indeed, in certain embodiments where the battery comprises a molten negative electrode, the temperature of the negative electrode during battery operation (or operating temperature) is from about 100 ° C to about 155 ° C. In other embodiments, the operating temperature of the battery is from about 110 ° C to about 150 ° C. In yet another embodiment, the operating temperature of the battery is from about 115 ° C to about 125 ° C. Further, in other embodiments where the negative electrode is in a molten state during battery operation, the battery operating temperature may be within any partial range of the above operating temperatures (eg, about 120 ° C. ± 2 ° C.). . In still other embodiments, the battery may be operated at higher temperatures, such as temperatures below 250 ° C, temperatures below 200 ° C, temperatures below 180 ° C, and the like.

  In embodiments where the negative electrode 20 remains in a solid state when the battery 10 is in operation (eg, embodiments in which the negative electrode comprises sodium intercalated carbon and / or a solid sodium anode), the battery performs the desired function. If present, the battery may function at any operating temperature. Indeed, in certain embodiments, the operating temperature of the battery is from about −20 ° C. to about 98 ° C. in embodiments where the negative electrode is solid when the battery is in operation. In other such embodiments, the operating temperature of the battery is from about 18 ° C to about 65 ° C. In other such embodiments, the operating temperature of the battery is from about 20 ° C to about 60 ° C. In other embodiments, the operating temperature of the battery is from about 30 ° C to about 50 ° C. In other embodiments, where the negative electrode remains solid when the battery is operating, the operating temperature of the battery is within any partial range of the aforementioned operating temperature (eg, about 20 ° C. ± 10 ° C.). There may be.

  In some embodiments (eg, when the negative electrode 20 is melted when the battery 10 is in operation), the negative electrode 20 is in direct contact (and / or wet) with the electrolyte membrane 40, while other embodiments (eg, In the case where the negative electrode remains in a solid state when the battery is activated), the negative electrode is not in direct contact with the electrolyte membrane. Indeed, as shown in FIG. 4, in some embodiments where the negative electrode 20 remains in a solid state when the battery 10 is in operation, the non-aqueous anolyte 65 separates the negative electrode 20 from the electrolyte membrane 40. In some embodiments, the non-aqueous anolyte may impart any suitable function, including but not limited to physical properties between the negative electrode and the electrolyte membrane to prevent negative electrode cracking and electrolyte membrane damage. A buffer material function may be provided.

  When the battery 10 has a non-aqueous anolyte 65, the anolyte is chemically compatible with the negative electrode 20 and the electrolyte membrane 40 and sufficiently conducts sodium ions from the negative electrode to the electrolyte membrane (and vice versa). It may consist of any suitable chemical substance that can In this regard, examples of suitable non-aqueous anolytes include, but are not limited to, propylene carbonate, ethylene carbonate, one or more organic electrolytes, ionic liquids, aprotic polar organic solvents, polysiloxane compounds, acetonitrile compounds Ethyl acetate; and / or other suitable non-aqueous liquids and / or gels. A more detailed description of a suitable non-aqueous anolyte is described in US 2011/0104526 (filed Nov. 5, 2010), which is incorporated herein by reference.

Referring to the sodium ion conducting electrolyte membrane 40, the membrane can selectively permeate sodium ions and any suitable material that allows the battery 10 to function with the non-aqueous cathode solution 35 or the aqueous cathode solution 35. May consist of: In one embodiment, the electrolyte membrane comprises a NaSICON type (Super Ion CONductive) material. If the electrolyte membrane is made of a NaSICON type material, the NaSICON type material may be made of any known or novel NaSICON type material, as long as it can be suitably used in the described battery 10. Examples of suitable NaSICON type composition, but are not limited _{to, Na 3 Zr 2 Si 2 PO} 12, Na 1 + x Si x Zr 2 P 3-x O 12 (x is from about 1.6 to about 2.4 ), Y- doped _{NaSICON (Na 1 + x + y} Zr-2 y Y y Si x P 3-x O 12, Na 1 + x Zr 2-y Y y Si x P 3-x O 12-y (x = 2, y = 0 .12)), Na _{1 + x} Zr ₂ Si _x P _3-x O ₁₂ (x is about 0 to about 3, and in some cases about 2 to about 2.5) and Fe-doped NaSICON (Na ₃ Zr _{2 / 3} Fe _4/3 P ₃ O ₁₂₎ can be mentioned. In one specific embodiment, the NaSICON-type film consists of Na ₃ Si ₂ Zr ₂ PO ₁₂ . In another embodiment, the NaSICON-type membrane is composed of one or more NaSELECT (registered trademark, manufactured by Ceramatec, Inc., Salt Lake City, Utah) material. In yet another embodiment, the NaSICON type membrane comprises a known or novel composite material, such as a cermet-supported NaSICON membrane. In such embodiments, the composite NaSICON membrane can include any suitable component, including, but not limited to, a porous NaSICON-cermet layer composed of NiO / NaSICON or other suitable cermet layer and a dense NaSICON Consists of. In yet another embodiment, the NaSICON film comprises a monoclinic ceramic.

  In some embodiments (as shown in FIGS. 5A and 5B), the electrolyte membrane 40 includes a first porous support 70 (eg, relatively thick and porous) that supports a layer 75 of relatively thin and dense NaSICON-type material. NaSICON type material). In such embodiments, the first porous support may perform any suitable function, such as acting as a scaffold for the dense layer. As a result, in certain implementations of the electrolyte membrane, losses due to polar resistance at the relatively low operating temperatures described above can be minimized. Further, in some embodiments, having both a porous skeleton and a dense NaSICON type layer allows the electrolyte membrane to have a relatively high mechanical strength (eg, within the battery 10 due to pressure on, operating, etc. the battery). Can withstand fluctuations in pressure).

  The porous support layer 70 may have any suitable thickness. In certain embodiments, the thickness is from about 50 μm to about 1250 μm. In another embodiment, the porous support layer has a thickness of about 500 μm to about 1000 μm. In yet another embodiment, the porous support layer has a thickness of about 700 μm to about 980 μm. In yet another embodiment, the thickness of the porous support layer is a more preferred range within the above range (eg, from about 740 μm to about 960 μm).

  The dense layer 75 on the support layer 70 may be any suitable thickness as long as the battery 10 functions as desired. Indeed, in certain embodiments, the thickness of the dense layer (eg, a dense layer of NaSICON type material) is from about 20 μm to about 400 μm. In other embodiments, the dense layer has a thickness of about 45 μm to about 260 μm. In yet another embodiment, the dense layer has a more preferred range of thickness within the above range (eg, about 50 μm ± 10 μm).

The electrolyte membrane 40 may have any suitable sodium conductivity as long as the battery 10 has a desired function. Indeed, in certain embodiments (eg, when the electrolyte membrane is comprised of NaSELECT® or other suitable NaSICON-type material), the electrolyte membrane is about 4 × 10 ⁻³ S / cm ⁻¹ to about 20 ×. It has a conductivity of 10 ⁻³ S / cm ⁻¹ (or a partial range thereof).

  If the electrolyte membrane 40 is made of a NaSICON type material, the NaSICON type material provides the battery 10 with some advantageous performance. For one, the NaSICON type material is substantially impermeable to water and stable, as opposed to the sodium β ″ -alumina ceramic electrolyte membrane, so the NaSICON type material is compatible with the sodium anode 20. It is possible to include a cathode solution 35 such as an insoluble aqueous cathode solution. Therefore, the use of a NaSICON type membrane as the electrolyte membrane gives the chemical substances that make up the battery a wide degree of freedom. Another advantageous performance related to the use of NaSICON type membranes is that such membranes have minimal capacity because they prevent the negative electrode 20 and positive electrode solution 35 from mixing while selectively transporting sodium ions. It makes it possible to have a battery storage period that is relatively stable at loss and at room temperature. Indeed, certain NaSICON-type materials (eg, NaSELECT® membranes) can eliminate self-discharge, crossover and / or related inefficiencies due to the permanent solid-solid selection of the material.

  Referring to current collector 30, battery 10 may comprise any suitable current collector as long as the battery can be charged and discharged as desired. For example, the current collector may consist of substantially any current collector shape as long as it can be suitably used in a sodium-based rechargeable battery system. In certain embodiments, the current collector is one or more wires, felts, plates, parallel plates, tubes, meshes, mesh screens, foams (eg, metal foams, carbon foams, etc.) and / or other suitable Consists of current collector shape. Indeed, in certain embodiments, the current collector comprises a shape having a relatively large surface area (eg, one or more mesh screens, metal foam, etc.).

The current collector 20 may be made of any suitable material as long as the battery 10 functions as desired. In this regard, examples of suitable current collector materials include, but are not limited to, carbon, platinum, copper, nickel, zinc, sodium intercalation materials (eg, Na _x MnO ₂ etc.), nickel foam, nickel , Sulfur complexes, sulfur halides (eg, sulfur chloride, etc.) and / or other suitable materials. Furthermore, these materials may be used alone or in combination. In certain embodiments, the current collector comprises carbon, platinum, copper, nickel, zinc and / or sodium intercalation material (eg, Na _x MnO ₂ ).

  The current collector 30 may be disposed at any suitable location in the positive electrode chamber 25 as long as the battery 10 functions as desired. In some embodiments, the current collector is disposed on the electrolyte membrane 40 (eg, as shown in FIG. 3) or in close proximity to the electrolyte membrane 40 (eg, as shown in FIG. 6). ).

  Referring to the cathode solution 35, the solution may be composed of any suitable sodium ion conductivity so long as the battery 10 functions as desired. Indeed, in certain embodiments, the positive electrode solution consists of an aqueous or non-aqueous solution. In this regard, examples of suitable aqueous solutions include, but are not limited to, dimethyl sulfoxide (DMSO), water, formamide, NMF, sodium hydroxide (NaOH) aqueous solution, ionic aqueous solution, and / or sodium ion and electrolyte membrane. 40 is composed of other aqueous solutions that are chemically compatible. Indeed, in certain embodiments, the cathode electrolyte solution comprises DMSO and / or formamide.

  In some embodiments, the positive electrode solution 35 comprises a non-aqueous solvent. In such embodiments, the positive electrode solution may consist of any suitable non-aqueous solvent as long as the battery 10 functions as desired. Examples of such non-aqueous solvents include glycerol, ethylene, propylene, and / or other non-aqueous solutions that are chemically compatible with sodium ions and electrolyte membrane 40.

In some embodiments (eg, an embodiment comprising a molten sodium negative electrode 20 and a sodium intercalating current collector 30 (eg, Na _x MnO ₂ ) as shown in FIG. 6), the positive electrode solution 35 is molten sodium-FSA (sodium-bis (Fluorosulfonyl) amide) electrolyte. In fact, Na-FSA has a melting point of about 107 ° C. (Na-FSA is melted at some typical operating temperature of battery 10) and Na-FSA has a conductivity in the range of about 50-100 mS / cm ^2. In certain embodiments, Na-FSA functions as a beneficial solvent (eg, for a molten sodium halide (NaX, X is selected from Br, I, Cl, etc.)). In this regard, Na-FSA has the following structure:

  When the positive electrode solution 35 consists of Na-FSA, the solution may consist of any suitable fluorosulfonylamide as long as it can conduct sodium ions to and from the electrolyte membrane and the battery 10 functions as desired. . Suitable examples of fluorosulfonylamides include, but are not limited to, 1-ethyl-3-methylimidazolium- (bis (fluorosulfonyl) amide (“[EMIM] [FSA]”) and other similar compounds. Can be mentioned.

  In certain embodiments, the cathode solution 35 also consists of one or more halogens and / or halogen compounds. In this regard, halogens and halogen compounds, as well as polyhalogen compounds and / or metal halide compounds formed therefrom (for example, when current collector 30 is made of a metal such as copper, nickel, zinc, etc. (described below)). Has a suitable function and is not limited to this, but, for example, acts as a positive electrode when the battery 10 is operating. Examples of suitable halogens include bromine, iodine and chlorine. Similarly, suitable examples of halogen compounds include bromide ions, polybromide ions, iodide ions, polyiodide ions, chloride ions and polychloride ions. The halogen / halogen compounds may be introduced into the cathode solution by any suitable method, and in certain embodiments they are added as NaX (X is selected from Br, I, Cl, etc.).

In certain embodiments, the positive electrode solution 35 comprises halogen (X) (eg, bromine or iodine) and / or a halogen compound, and the battery is a negative reaction of the negative electrode 20, the positive electrode / current collector 30, and the overall reaction during battery operation. Have the following reactions.
Negative electrode: Na ← → Na ⁺ + 1e ⁻
Positive electrode: 2X ⁻ + 2e ⁻ ← → X ₂
Overall: 2Na + X ₂ ← → 2Na ⁺ + 2X ⁻
Therefore, when X is iodine, the battery 10 has the following chemical reaction, theoretical voltage (V), and theoretical specific energy (Wh / kg).
Negative electrode: Na ← → Na ⁺ + 1e ⁻ (−2.71 V)
Positive electrode: 2I ⁻ + 2e ⁻ ← → I ₂ (0.52V)
Overall: 2Na + I ₂ ← → 2Na ⁺ + 2I ⁻ (3.23 V) (581 Wh / kg)
Further, when X is bromine, the battery has the following chemical reaction and theoretical voltage and theoretical specific energy.
Negative electrode: Na ← → Na ⁺ + 1e ⁻ (−2.71 V)
Positive electrode: 2Br ⁻ + 2e ⁻ ← → Br ₂ (1.08 V)
Overall: 2Na + Br ₂ ← → 2Na ⁺ + 2Br ⁻ (3.79 V) (987 Wh / kg)

  The various components in the cathode solution 35 may be present in any suitable concentration as long as the battery 10 functions as desired.

In some embodiments, a halogen (eg, bromine, iodine or chlorine) is formed during operation (eg, charging) in battery 10. In this regard, halogen has several effects when the battery is in operation. In one example, the halogen produced in the cathode solution 35 has a relatively high vapor pressure, exposing the battery to undesirable pressures. In other examples, halogens in the cathode solution react with chemicals in other solutions to produce undesirable chemicals (eg, HOX and / or HX, the cathode solution is aqueous, X is Br, I etc.). In certain embodiments, the battery is modified to reduce the total amount of halogen molecules (eg, bromine, iodine, etc.) present in the positive electrode solution in order to reduce and / or prevent problems with the halogens generated in the positive electrode solution. In some embodiments, the battery is modified to operate to control the amount of halogen present in the cathode solution.

In certain embodiments, to reduce the amount of halogen in the cathode solution 35, the solution may include an excess amount of sodium halogen compound (eg, sodium bromide, sodium iodide, sodium chloride, etc.) and / or an excess amount. Consists of halogen molecules (for example, bromine, iodine, chlorine, etc.). In such embodiments, the positive electrode solution forms one or more polyhalogen compounds (eg, Br ₃ ⁻ , I ₃ ⁻ , Cl ₃ ^−, etc.) in the positive electrode solution 35 (shown in FIG. 2, where X is Br). A suitable amount of sodium halogen compounds and / or halogen molecules . In such embodiments, the polyhalogen compound has an electronic activity similar to the corresponding halogen while having a lower vapor pressure than the corresponding halogen.

In some embodiments, the amount of halogen in the cathode solution 35 is reduced so that the cathode solution is adducted with halogens, halogen compounds and / or polyhalogen compounds in the cathode solution (eg, halogen compound-amine adduct, One or more complexing agents having the ability to form a complex or other performance such as a halogen compound-ammonia adduct. In this regard, complexing agents consist of chemicals that can form adducts and / or complexes with halogens, halogen compounds and / or polyhalogen compounds in the cathode solution. Examples of such complexing agents include, but are not limited to, one or more bromide-amine adducts, iodide-amine adducts, chloride-amine adducts, tetramethylammonium halogen compounds (eg, odor Tetramethylammonium iodide, tetramethylammonium iodide, tetramethylammonium chloride, etc.), ammonium compounds, N-methyl-N-methylmorpholine halogen compounds, and the like. Indeed, in certain embodiments, the positive electrode solution consists of NaBr / Br ₂ and the complexing agent consists of tetramethylammonium bromide and reacts with bromine to form tetramethylammonium tribromide. In some other embodiments (for example, as shown in FIG. 4, the anode chamber 15 includes a non-aqueous anolyte 65, the cathode solution 35 comprises NaBr / Br ₂ , and the current collector 30 comprises carbon). The complexing agent consists of N-methyl-N-methylmorpholine bromide.

In one embodiment, to reduce the amount of halogen produced in the positive electrode solution 35, a metal halide is formed based on the metal used in the battery 10, current collector and the halide ion in the solution. By using such a metal current collector 30, generation of halogen (for example, bromine, iodine, chlorine, etc.) is avoided. Such a process may be performed in any suitable manner, but in certain embodiments, the metal in the current collector is oxidized before the halide ion in the cathode solution is oxidized to form the corresponding halogen. It depends on the method. Thus, a result, the non-volatile metal halogen compounds _{(e.g., CuBr, NiBr 2, ZnBr 2} , CuI, NiI 2, ZnI 2 or the like) is formed. In this regard, the current collector may be composed of any suitable metal such that halogen generation can be avoided by forming a metal halide during the operation of the battery. Examples of such metals include copper, nickel, zinc, combinations thereof and alloys thereof. In this regard, an example of the corresponding half-cell reaction of a battery comprising such a metal current collector is given below.
Cu + X ⁻ ← → CuX + 1e ⁻
Ni + 2X ⁻ ← → NiX ₂ + 2e ⁻
Zn + 2X ⁻ ← → ZnX ₂ + 2e ⁻
Furthermore, an example of the total reaction of the NaBr / Br ₂ battery 10 having the nickel current collector 30 is represented by the following reaction formula.
2Na + NiBr ₂ ← → 2NaBr + Ni

A battery having a metal current collector 30 has a wide variety of electromotive forces, the battery 10 includes NaBr / Br ₂ in the positive electrode solution 35, and in the case where the current collector is made of copper, nickel or zinc, The electromotive forces generated from such batteries are about 2.57V, about 2.61V, and about 2V, respectively.

In still other embodiments, the battery 10 may be modified using any suitable combination described above to reduce the total amount of halogen (eg, bromine, iodine, etc.) in the positive electrode chamber 25. In some embodiments of the battery, including but not limited to, the battery includes a current collector 30 comprised of copper, nickel, zinc or other suitable metal, and the cathode solution 35 comprises a complexing agent, an excess amount of sodium halide. And / or an excess of halogen molecules .

  Referring to terminals 45 and 50, battery 10 may have any suitable terminal as long as the battery can be electrically connected to an external circuit (not shown). External circuits include but are not limited to one or more batteries. In this regard, the terminals may be made of any suitable material, shape, and size.

  Referring to FIGS. 1A and 2A, a further embodiment of battery 10 is shown. 1A and 2A are similar to the embodiment shown in FIGS. 1 and 2, respectively, but FIGS. 1A and 2A have additional components (FIG. 1A shows the discharge state of battery 10 and FIG. Indicates the state of charge of the battery 10). Specifically, FIG. 1A and FIG. 2A show that a sodium-halogen secondary battery 10 includes a negative electrode chamber 15 including a sodium-based negative electrode 20 and a positive electrode chamber 25 including a current collector 30 disposed in a liquid positive electrode solution 35, respectively. The sodium ion conductive electrolyte membrane 40 for separating the negative electrode from the positive electrode solution, the first terminal 45, the second terminal 50, the external reservoir 55 for storing the positive electrode solution, and the positive electrode solution from the reservoir through the current collector in the positive electrode chamber FIG. 9 shows a selling embodiment comprising a pump mechanism 60 configured to be pushed forward.

  The pump mechanism 60 will be described. The battery 10 may have any suitable pump mechanism as long as the fluid can be pushed from the reservoir 55 to flow into the battery. In fact, in FIG. 7A, the battery 10 is connected to a pump mechanism 60 configured as a pump that allows the first reservoir 55 and the positive electrode solution 35 to pass from the reservoir to the current collector 30 in the positive electrode chamber 25. An embodiment is shown. In some embodiments (also shown in FIG. 7A), the battery 10 is further connected to a second reservoir 56 and a second pump mechanism 62. In such an embodiment, the second pump mechanism pushes liquid (eg, molten sodium, non-aqueous anolyte 65, second anolyte, etc.) from the second reservoir 56 and flows through the negative electrode chamber 15. If possible, it may consist of any suitable pump. Although the pump mechanism that pushes fluid through the negative electrode chamber provides various advantageous performances to the battery, in certain embodiments, such a configuration can in any case reduce the total amount of sodium in the negative electrode chamber, thereby providing: If the positive electrode solution 35 comes into contact with the negative electrode 20, damage and / or danger can be reduced. Further, in certain embodiments, the battery can limit the amount of positive electrode solution in the battery by pumping out the positive electrode solution leading to the positive electrode chamber, thereby limiting or controlling the amount of halogen present in the battery. I can do it.

  When the battery 10 is coupled to one or more pump mechanisms (eg, 60 and 62) and / or reservoirs (eg, 55 and 56), the pump mechanism is connected to the batteries (eg, the positive electrode chamber 25 and / or the negative electrode chamber 15). The battery is designed to be able to pass at any suitable flow rate so that the battery performs the desired function. In this regard, the specific flow rates of the various embodiments of the battery depend on the solubility of the various materials in the positive electrode solution 35, the material of the negative electrode chamber 15 and / or the desired charge and / or discharge rate of the battery.

  Pump mechanisms (eg, 60 and 62) and / or reservoirs (eg, 55 and 56) may be added in other embodiments in addition to the embodiment shown in FIGS. 1A, 2A, and 7A. For example, FIG. 4A shows one embodiment of a similar battery 10 described in connection with FIG. However, in the embodiment of FIG. 4A, a pump mechanism 60 and reservoir 55 are added to the battery 10 to deliver the positive electrode solution 35 in contact with the electrode 30. Similarly, with respect to FIG. 6A, the battery 10 is similar to the battery shown in FIG. 6, but a pump mechanism 60 and a reservoir 55 are added to the battery 10 to deliver the cathode solution 35 in contact with the electrode 30. . Further, in the embodiment of FIG. 7A, one or more pump mechanisms 60, 62 and / or one or more reservoirs 55, 56 may be configured to be removed.

  In other embodiments, the negative electrode chamber 15 and the positive electrode chamber 25 can take any suitable dimensions, but as shown in FIGS. 1A, 2A, 3A and 4A, 6A and 7A, at least in some embodiments, the positive electrode solution The positive electrode chamber 25 is relatively small so that a substantial portion of 35 is stored outside the positive electrode chamber (eg, one or more external reservoirs 55 designed to store a portion of the positive electrode solution). . Such a configuration can impart a variety of functions to the battery 10. In some embodiments, having a relatively small positive electrode chamber allows the battery to have a relatively small amount of positive electrode solution in the positive electrode chamber, thereby collecting the majority of the positive electrode solution in the positive electrode chamber as current collector 30. Can be contacted.

  In addition to the above configuration, the battery 10 may optionally have any other suitable components and properties. By way of non-limiting illustration, FIG. 6 illustrates one embodiment of the battery 10 having one or more heat management systems 80. In certain embodiments, the battery may have any suitable type of heat management system that can maintain the battery within a suitable operating temperature range. Such heat management systems include, but are not limited to, for example, a heater, heat exchanger, cooler, one or more temperature sensors, and / or appropriate temperature control circuitry.

  As an example of other suitable components used in battery 10, one embodiment of the battery has one or more collectors (collector, not shown) between reservoir 55 and cathode electrolyte solution chamber 25. . Such a collector may perform any suitable function, and in certain embodiments, the collector collects halogen (eg, bromine, iodine, etc.) from the liquid cathode solution 35 as the solution flows through the collector. Used for.

  In other embodiments, the battery 10 can be modified to any suitable method as long as it can transport sodium from the negative electrode chamber 15 to the positive electrode chamber 25 during discharge. In this regard, certain embodiments of the described battery 10 have a battery case (not shown) that supplements the volume.

  In other embodiments, the positive electrode solution 35 may contain any other suitable component as long as the battery 10 has the desired function. Indeed, in certain embodiments, the positive electrode solution is carbon (eg, powdered carbon, carbon-containing material, etc.) and / or the solution is sodium conductive and is chemically compatible with the electrolyte membrane 40 and the current collector 30. Any other material may be included as long as it is soluble.

  In other embodiments, the battery 10 may be modified by any suitable method as long as the battery 10 can improve battery safety while having the desired function. Indeed, in certain embodiments, the battery may have one or more pressure relief valves (not shown). In other embodiments, the battery may have one or more external protective covers. Further, in other embodiments, the battery may be divided into two or more smaller batteries to reduce the risk associated with the battery being damaged or becoming inoperable. In other embodiments, in addition to the electrolyte membrane 40, the battery has one or more separators between the negative electrode 20 and the positive electrode solution 35, even if the electrolyte membrane is damaged, between the negative electrode and the positive electrode solution. Exposure can be minimized.

As another example of how to modify battery 10, certain embodiments of the battery are designed to control the pressure in a portion of the battery, such as, but not limited to, positive electrode chamber 25 and / or negative electrode chamber 15. Pressure management system. The pressure management system can perform any suitable function, and in certain embodiments, the halogen is other species in the cathode solution 35 (eg, excess sodium halide, excess halogen molecule , one or more complexing agents). Since the halogen is retained in the solution so that it can chemically react with the metal ions from the current collector 30), a sufficiently high pressure in the positive electrode chamber can be maintained.

  In addition to the above advantages of battery 10, the described battery has several other advantages. According to an embodiment, by enabling operation in a temperature range of less than about 150 ° C., battery 10 can operate at a much lower temperature compared to a conventional rechargeable molten sodium battery. Thus, the described battery can reduce the heat required during battery operation and / or dissipate the heat from the battery, is safer to handle and environmentally friendly. In addition, rechargeable conventional sodium batteries that operate at relatively high temperatures require relatively expensive construction materials (eg, metal or ceramic members, glass seals and / or members that are compatible with thermal expansion). In the battery embodiment described, the battery can be made using less expensive materials (eg, polymeric material, epoxy, epoxy and / or plastic mechanical seal members (eg, O-ring 85, lid 90, 3 shows a tube-like flange 92, etc. Fig. 3A shows a tube-like configuration in which one chamber (eg, negative electrode chamber 15) is at least partially disposed within another chamber (eg, positive electrode chamber 25). An embodiment is shown in addition to the battery 10 having (the contents of these two chambers remain separated by the electrolyte membrane 40 and other partition walls).

  In other embodiments, certain embodiments of the described battery 10 can maintain a suitable operating temperature through Joule heating. As a result, such batteries are relatively efficient because no additional energy is required to maintain such batteries at high operating temperatures.

Other embodiments of the described battery 10 are compared to competing conventional batteries (eg, a Na / S battery having a theoretical voltage of about 2.07V, a Zn / Br ₂ battery having a theoretical voltage of about 1.85V. And a relatively high theoretical battery voltage (e.g., about 3.23V to about 3.79V). Furthermore, certain embodiments of the described battery are compared to competing conventional batteries (eg, about 755 Wh / kg for Na / S rechargeable batteries, about 428 Wh for Zn / Br ₂ rechargeable batteries). / Kg) has a relatively high theoretical specific energy (eg, about 987 Wh / kg for NaBr / Br ₂ cells, about 581 Wh / kg for NaI / I ₂ cells). Similarly, certain embodiments of the described battery are compared to competing conventional batteries (eg, the actual specific energy of a Na / S battery is about 150 to about 240 Wh / kg, the actual of a Zn / Br ₂ battery Specific energy (compared to about 65 Wh / kg), which has a relatively high actual specific energy (eg, about 330 to about 440 Wh / kg in the NaBr / Br ₂ battery embodiment).

  As a result of the relatively high voltage and specific energy associated with the described battery 10 embodiment, it is in lesser embodiments that it is necessary to achieve the same voltage and specific energy obtained with competing conventional batteries. . In this regard, the use of these fewer batteries can reduce the amount of battery interconnection hardware, the charge control circuitry required to obtain the desired voltage and desired specific energy, and the like. Thus, certain embodiments of the described battery can reduce the overall battery complexity and reduce the total cost excluding the battery, interconnect hardware, charge control circuitry, and the like. Furthermore, as a result of the relatively high capacity and voltage of batteries, such batteries can be used in a wide variety of fields, such as but not limited to grid scale energy storage systems and electric vehicles. Is mentioned.

As yet another advantage, certain embodiments of the described battery 10 have relatively long cycle characteristics compared to competing conventional batteries (eg, about 5000 deep in the case of NaBr / Br ₂ battery embodiments). Cycle for Na / S batteries, about 2000 cycles for Zn / Br ₂ batteries). In addition, because the described battery embodiments allow for effective utilization of sodium and halogen during cycling, such embodiments have a relatively higher discharge / charge cycle compared to conventional batteries. Deep (eg, high SOC (charged state) and DOD (deep discharged state) of about 70% to about 80%).

  In yet another example, certain embodiments of the described battery 10 have high sodium ion mobility via an electrolyte membrane 40 (eg, a fully dense NaSICON type material on a porous support), and redox. The reaction rate is relatively fast, especially at low and medium temperatures (eg, from ambient temperature to about 150 ° C.) as described herein, resulting in a relatively high current (hence high power).

  Referring to FIG. 14, a further embodiment of battery 10 can be shown and illuminated. Embodiments of the present invention include a sodium ion conducting electrolyte membrane 40 such as a NaSICON membrane sold as NaSELECT (Ceramatec, Inc., registered trademark of Salt Lake City, Utah). The battery 10 also includes a sodium-based negative electrode 20 and is made of sodium metal in the embodiment of FIG. The negative electrode is accommodated in the negative electrode chamber 15. Sodium ions are transferred from the negative electrode 20 to the positive electrode chamber 25 through the sodium ion conductive electrolyte membrane 40, respectively. The current collector 30a may be used in the negative electrode chamber 15 as necessary. One skilled in the art will understand the specific types of materials used for the current collector 30a.

The positive electrode chamber 25 includes a current collector 30, and in this case is made of a carbon current collector (although other materials (for example, metal) can be used). The liquid cathode solution 35 is stored in the cathode chamber 25. In the embodiment of FIG. 14, this solution consists of a mixture of NaBr / Br _{2 in} a solvent. Of course, other halogen / halogen compound-containing materials can also be used.

In the embodiment of FIG. 14, battery 10 is constructed from a molten sodium anode and an aqueous or non-aqueous bromine cathode. The theoretical electromotive force of this battery is 3.79V. Since the melting point of Na metal is about 100 ° C., the battery operates at about 110 ° C. or higher, preferably about 120 ° C. or higher. Catholyte of this embodiment is defined with an excess of sodium bromide with bromine molecules, Br ₃ ^- form the sodium such as polyhalogenated compound. These species have a lower vapor pressure while having the same electronic activity as bromine (bromine is described as a halogen compound material, but of course other halogen compounds can be used).

The embodiment of FIG. 14 has special advantages. For example, one of the potential uses related to the invention of this embodiment is its use as a large-scale secondary battery such as a grid scale energy storage system (ESS) and an electric vehicle (EV) market. Furthermore, the membrane 40 has a room temperature conductivity of about 5 × 10 ⁻³ S / cm. Furthermore, the NaSICON film is completely unreactive with moisture and other common solvents (eg, methanol).

Referring to FIG. 14, a further embodiment is configured such that a chemical species is added to the liquid cathode solution 35 to form a bromine and / or polybromide adduct, such as a bromide amine adduct. . The following is an example of tetramethylammonium bromide that functions as a complexing agent.
Br ₂ + tetramethylammonium bromide ← → tetramethylammonium tribromide In one embodiment, the membrane is a NaSICON tube so that the battery system can withstand pressure. The pressure load is used to keep bromine in the solution.

Referring to FIG. 15, another embodiment of battery 10 is shown. This embodiment of battery 10 is similar to the embodiment shown in FIG. However, in the embodiment of FIG. 15, battery 10 avoids the generation of bromine by utilizing a metal current collector 30 that forms the corresponding bromide. The cathode half-cell reaction is shown below.
Cu + Br ⁻ ← → CuBr + e ⁻
Ni + 2Br ⁻ ← → NiBr ₂ + 2e ⁻
Zn + 2Br ⁻ ← → ZnBr ₂ + 2e ⁻
The total reaction in the battery is
2Na + NiBr ← → 2NaBr + Ni

  The battery 10 is based on oxidation of the metal before bromine ions are oxidized to bromine to form a non-volatile metal bromide. The electromotive forces of these batteries are 2.57V, 2.61V, and 2V in the case of Cu, Ni, and Zn, respectively. The battery contains a bromide or bromine electrode, a complexing agent and an aqueous or non-aqueous solvent at 120 ° C. The battery also includes a NaSICON film that is stable in this state.

  Referring to FIG. 16, a further embodiment of battery 10 is shown. In the embodiment of FIG. 16, battery 10 includes a sodium anode. However, as shown in FIG. 15, battery 10 includes a sodium-inserted carbon anode 20a. The positive electrode chamber 25 is composed of an aqueous or non-aqueous bromine or bromide solution used as the liquid positive electrode solution 35. The anolyte 60 is disposed in the vicinity of the film 40 (which may be a NaSICON film).

The battery 10 of FIG. 16 may be operated at a temperature of room temperature to 60 ° C., and when bromine molecules are effectively complexed (for example, N-methyl-N-methylmorpholinium bromide), free bromine. Decreases as it exceeds 100 times. Other complexing agents can be used as long as they can effectively complex bromine at room temperature (MEMBr is used in a zinc-bromine system). In one embodiment, the battery 10 uses a non-aqueous anolyte 65 in / between sodium-inserted carbon and NaSICON membrane 40.

  The specific embodiment of the battery 10 shown in FIG. 16 uses bromide or bromide as the halogen / halogen compound material in the positive electrode chamber 25. NaSICON membranes are stable at room temperature in contact with this aqueous or non-aqueous solvent. The battery 10 allows reversible plating of Na and may have a bromine cathode. The battery can perform at least 25 reversible cycles at the actual C-rate (C / 5) and the actual depth of discharge (DOD ≧ 50%).

  Referring to FIG. 17, a further embodiment of battery 10 is shown. This battery uses a Zn negative electrode 20b and a positive electrode (a current collector is used in the positive electrode chamber 25, but this feature is not shown in FIG. 17). The battery 10 uses a dense NaSICON membrane 40 that is selectively permeable to sodium ions and impermeable to water. The anolyte 65 and the liquid cathode solution 35 are sodium bromide solutions and not zinc bromide solutions.

In this battery 10, the Zn anode 20b is disposed in an aqueous solution containing sodium bromide (or other alkali metal ion and halogen compound ion solution). The anode shown in this figure is Zn, but other metals can be used. The liquid cathode solution 35 (catholyte) is a bromine / sodium bromide solution and a graphite current collector. During discharge, Zn oxidizes to form zinc bromide and sodium ions are transferred to the cathode current collector and react with bromine to form sodium bromide. During charging, Zn precipitates again and bromine is regenerated. The advantages of this battery 10 over the microporous battery are as follows.
(1) The anolyte composition can be adjusted to reversibly precipitate Zn. In fact, the anolyte is a mixture of NaBr and NaOH and does not form zinc dendrites that cause battery capacity loss.
(2) Since bromine from the catholyte does not come into contact with zinc metal, self-discharge does not occur.
(3) Special electrolyte compounds are used to avoid the need for anolyte and catholyte flow.
(4) When a non-aqueous solvent is used, other lower reduction potential elements such as Mg can be used, resulting in a higher electromotive force battery.

  This embodiment of battery 10 may have a sodium hydroxide solution in a Zn anode and / or NaSICON based battery in sodium bromide, the arrangement being reversible. The NaSICON film in this cell is stable to the presence of bromide / bromine / complexing agent / aqueous or non-aqueous solvent at room temperature.

The battery 10 may be configured to perform reversible NaBr / Br ₂ cathode operation at room temperature. This battery 10 is a flowless battery using a Zn anode and a NaBr / Br ₂ cathode, at least 25 times at the actual C-rate (C / 5) and the actual depth of discharge (DOD ≧ 50%). A reversible cycle can be performed.

  The following examples show various embodiments included in the gist of the present invention. It should be understood that these examples are illustrative only and are not exhaustive examples of the various embodiments that can be prepared.

Example 1:
In this embodiment, battery 10, molten sodium anode 20, platinum mesh current collector 30, 20 wt% NaI formamide consisting cathode solution _{(I 2} versus NaI molar ratio = 1: 3, 5 to formamide as a positive electrode Weight% carbon). In this example, after operating for over 2000 minutes at a temperature up to about 120 ° C., the battery had battery characteristics as shown in FIG. Specifically, FIG. 8 shows that the charge / discharge curve of the battery is relatively noisy and some overvoltage is also occurring. In this regard, these noise curves and overvoltages are believed to be the result of the use of formamide. Because formamide only dissolves NaI, not iodine, formamide produces gas bubbles, and formamide has a lower conductivity compared to other suitable solvents that can be present in cathode solution 35. is there. Nevertheless, FIG. 8 shows at least one embodiment showing that a NaI / NaI ₂ battery is feasible.

Example 2:
In Example 2, the battery 10 includes a molten sodium negative electrode 20, a platinum mesh current collector 30, a positive electrode solution composed of less than about 25% by weight NaI and more than about 75% DMSO, 5 mA / cm ^{2 to} 10 mA / cm ² . Prepared to include a NaSICON type membrane with current density. In this example, after operating for more than 150 hours at a temperature of up to about 120 ° C., the battery had battery characteristics as shown in FIG. Specifically, FIG. 9 shows that this battery had a lower overvoltage compared to the battery of Example 1. In this regard, it is believed that the DMSO solution has higher conductivity compared to formamide, thereby causing the battery to have a lower overvoltage. Furthermore, in this example, it is clear that DMSO dissolves NaI and iodine. Furthermore, DMSO is believed to have a stable electrochemical window that can operate the battery better than the battery in Example 1. Thus, it is clear from this example that DMSO can be used as a better solvent than formamide, at least in some embodiments.

Example 3:
In Example 3, the first large battery comprises an electrolyte membrane 40 having a surface area that is four times the surface area of the membrane used in Examples 1 and 2 at a current density of about 3.65 mA / cm ² , a molten sodium negative electrode 20, It is prepared containing a positive electrode solution 35 consisting of platinum mesh current collector 30 and about 25 wt% (relative to 1 mol of NaI containing 0.5 mole of _{I 2)} less NaI and about 75 wt% more than formamide . Further, the second large battery has an electrolyte membrane 40, a molten sodium negative electrode 20, a platinum mesh collector having a surface area that is four times the surface area of the membrane used in Examples 1 and 2 at a current density of about 3.65 mA / cm ^2. collector 30, was prepared to contain a positive solution 35 consisting of about 25 weight percent of NaI and DMSO greater than about 75 wt% (relative to 1 mol of NaI containing 0.5 mole of _{I 2).} These two batteries have the battery characteristics of the first battery and the second battery after operating at a temperature of up to about 120 ° C. for more than 120 hours at a discharge depth of about 20% of the available capacity of the battery. The summary is shown in FIG. 9 and FIG. Specifically, FIGS. 10 and 11 show that two batteries have practically ideal battery characteristics. Furthermore, in the second battery of the present example, FIG. 12 shows a part having battery characteristics when operated at a discharge depth of about 50% of the available capacity of the battery. In this regard, FIG. 12 shows that it is feasible to operate a battery with a relatively deep cycle (deep discharge depth).

Example 4:
In this example, the battery 10 includes a molten sodium negative electrode 20, an electrolyte film 40 made of a NaSICON type film having a current density of about 10 mA / cm ^2, and a positive electrode solution made of a solution in which NaI / I ₂ is dissolved in an organic solvent and added carbon. 35 was prepared. The cell was operated at about 110 ° C. for over 30 hours. FIG. 13 shows a part of the battery characteristics of the test run of the battery of this example. In this regard, FIG. 13 shows that the voltage drop of this example battery is relatively large and that there is noise in the data. However, FIG. 13 also shows the feasibility of a sodium-halogen battery using iodine.

Thus, the above examples illustrate the implementation of Na-iodine batteries using DMSO or NMF as a solvent that dissolves sodium iodide and (at least in part) also dissolves iodine. These systems allow a NaI / iodine cathode discharge depth of about 50%, and preferably a NaI / iodine cathode discharge depth of about 70%. In some embodiments, the Pt cathode may be replaced with a low cost cathode. The film used for the battery may be a NaSICON film or may have a current density of 10 mA / cm ² or more.

  The batteries described herein have significant advantages over other types of batteries. For example, as described above, various known sodium rechargeable batteries must be operated at high temperatures, such as above 250 ° C or above 270 ° C. However, as described in the present invention, this embodiment can operate at temperatures below 250 ° C. Indeed, in certain embodiments, the operating temperature is ambient, less than about 60 ° C, less than about 150 ° C, less than 200 ° C, less than 180 ° C. Or the temperature. These operating temperature ranges of the battery provide a significant effect because they do not require resources to heat the battery to a very high temperature (eg, 270 ° C.).

  In addition, some of the embodiments use NaSICON instead of sodium β ″ -alumina ceramic material as a separator. NaSICON has particular advantages over sodium β ″ -alumina ceramics because it is compatible with water and other organic solvents. In addition, NaSICON does not have the problem of reactions on one side of the membrane contaminating / preventing reactions on the other side of the membrane, optimizing each side of the membrane and splitting the battery into two parts I can do it.

  All applications and patent documents mentioned in this invention are incorporated herein by reference.

  The embodiments of the present invention can be implemented in other specific ways without departing from the spirit and essential performance of the present invention. The described embodiments and examples are merely exemplary in any way and are not intended to limit the invention. The gist of the present invention is indicated by the appended claims rather than the foregoing description. All modifications within the scope and the equivalent of the claims are also included in the scope of the present invention.

Claims (31)

A sodium-halogen comprising a negative electrode chamber comprising a negative electrode made of sodium, a positive electrode chamber comprising a current collector disposed in the positive electrode solution, and a sodium ion conductive electrolyte membrane comprising a NaSICON type material separating the negative electrode from the positive electrode solution. a secondary battery, the negative electrode during discharge to release sodium ions are electrochemically oxidized, the negative electrode of the sodium metal was formed by reducing electrochemically sodium ions during charging, the positive electrode solution halogen And a sodium halogen compound selected from NaBr, NaI and NaCl, wherein the amount of the sodium halogen compound in the positive electrode solution reacts with the halogen to form a sodium polyhalogen compound, thereby reducing the halogen content in the positive electrode solution. Sodium-halogen secondary battery, characterized in that it is in excess of an amount sufficient for   The secondary battery according to claim 1, wherein the negative electrode is made of molten sodium metal.   The secondary battery according to claim 1, which can operate at a temperature of the negative electrode of less than 150 ° C.   The secondary battery according to claim 3, which can operate at a temperature of the negative electrode of less than 100 ° C.   The secondary battery according to claim 1, which can operate at a temperature of the negative electrode of less than 250 ° C.   The secondary battery according to claim 1, which can operate at a temperature of the negative electrode of less than 200 ° C.   The secondary battery according to claim 1, which can operate at a temperature of the negative electrode of less than 180 ° C.   The secondary battery according to claim 1, wherein the negative electrode is made of a material selected from sodium metal and sodium intercalation carbon.   The secondary battery according to claim 8, wherein the negative electrode remains as a solid during the operation of the secondary battery.   The secondary battery according to claim 8, which can operate at a temperature of the negative electrode of less than 60 ° C.   Furthermore, the secondary battery of Claim 8 which has a non-aqueous negative electrode solution arrange | positioned between a negative electrode and an electrolyte membrane.   The secondary battery according to claim 1, wherein the NaSICON type material comprises a composite film comprising a porous layer and a dense functional coating layer.   The secondary battery according to claim 1, wherein the positive electrode solution comprises a solvent selected from the group consisting of N-methylformamide and dimethyl sulfoxide.   The secondary battery according to claim 1, wherein the positive electrode solution contains a complexing agent capable of forming a complex with at least one of a halogen, a sodium halogen compound, and a polyhalogen compound in the positive electrode solution. The secondary battery according to claim 14 , wherein the complexing agent comprises a tetramethylammonium halogen compound.   The secondary battery according to claim 1, wherein the current collector is a metal selected from the group consisting of copper, nickel, zinc, and combinations thereof.   And a first reservoir in fluid communication with the positive electrode chamber and a first pump mechanism configured to flow the positive electrode solution from the first reservoir to the positive electrode chamber and to pass the current collector. Item 11. The secondary battery according to Item 1.   A second liquid flow reservoir in which the negative electrode is made of molten sodium metal and is in fluid flow with the negative electrode chamber; and a second pump mechanism configured to flow molten sodium metal from the second reservoir to the negative electrode chamber; The secondary battery according to claim 17, comprising: A negative electrode chamber comprising a sodium metal negative electrode, a positive electrode chamber comprising a current collector disposed in a positive electrode solution comprising a halogen and a sodium halogen compound selected from NaBr, NaI and NaCl, and a NaSICON type for separating the negative electrode from the positive electrode solution A molten sodium secondary battery comprising a sodium ion conductive electrolyte membrane comprising a material , wherein the sodium metal negative electrode is electrochemically oxidized during the discharge of the battery to release sodium ions, and the sodium is discharged during the recharging of the battery. Ions are electrochemically reduced to form sodium metal, the sodium metal negative electrode is melted during battery operation, and the amount of sodium halogen compound in the positive electrode solution reacts with the halogen to produce sodium polyhalogen compound. formed, is in excess of the amount sufficient to reduce the halogen content of the positive electrode solution, it Molten sodium secondary battery characterized. The secondary battery according to claim 19 , wherein the secondary battery is operable at a temperature of 100 ° C. to 150 ° C. The secondary battery according to claim 19 , wherein the positive electrode solution contains a complexing agent. The secondary battery according to claim 21 , wherein the complexing agent comprises a tetramethylammonium halide compound material. The secondary battery according to claim 19 , wherein the positive electrode solution comprises a molten sodium halogen compound dissolved in molten fluorosulfonylamide. The secondary battery according to claim 23 , wherein the fluorosulfonylamide comprises 1-ethyl-3-methylimidazolium- (bis (fluorosulfonyl) amide. The secondary battery according to claim 19 , wherein the current collector is made of a sodium intercalation material. Furthermore, claims having a first reservoir in communication with positive electrode chamber and liquid flow, and a first pump mechanism a positive solution to flow from the first reservoir to the positive electrode chamber, which is configured to pass a current collector Item 20. The secondary battery according to Item 19 .   A negative electrode chamber comprising a negative electrode; a positive electrode chamber comprising a current collector disposed in a positive electrode solution comprising at least one of halogen and a halogen compound; a sodium ion conductive electrolyte membrane separating the negative electrode from the positive electrode solution; and the negative electrode and an electrolyte A secondary battery comprising a non-aqueous negative electrode solution disposed between membranes, wherein the negative electrode is made of a material selected from sodium metal and sodium intercalated carbon anode, the negative electrode being electrochemical during discharge of the battery To release sodium ions, the negative electrode electrochemically reduces sodium ions to form sodium metal during battery recharging, and the negative electrode remains in a solid state during secondary battery operation, A secondary battery wherein the sodium ion conductive electrolyte membrane is made of a NaSICON type material. The secondary battery according to claim 27 , wherein the secondary battery is operable when the temperature of the negative electrode is less than 60 ° C. The secondary battery according to claim 27 , wherein the positive electrode solution contains a complexing agent. 30. The secondary battery according to claim 29 , wherein the complexing agent comprises a halogenated N-methyl-N-methylmorpholine compound. Furthermore, claims having a first reservoir in communication with positive electrode chamber and liquid flow, and a first pump mechanism a positive solution to flow from the first reservoir to the positive electrode chamber, which is configured to pass a current collector Item 27. The secondary battery according to item 27 .